JP3017604B2 - Fixing device and image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer, and a fixing rotator and a pressing rotator used in the image forming apparatus. To a fixing device and an image forming apparatus for heating the sheet by using a halogen lamp.

[0002]

2. Description of the Related Art A conventional fixing device employs a method in which a rotary member is heated from the inside of a fixing rotary member or a pressing rotary member by using a halogen lamp. In order to stabilize the fixing state of an image fixed on a material, it is necessary to make the temperature distribution on the surface of the heated rotating body uniform in the axial direction of the rotating body.

[0003] However, in a commonly used fixing or rotating rotator, heat is escaping to the axial end of the rotator and radiation irradiating the inner surface of the rotator with radiation from a halogen lamp. Due to two factors, that is, the tendency to decrease at the axial end, the surface temperature of the rotating body tends to decrease at the axial end.

Therefore, conventionally, as a means for avoiding a decrease in the surface temperature at the axial end of the rotating body, a distribution of the amount of radiation supplied from a halogen lamp to the inner surface of the rotating body (hereinafter referred to as a light distribution). There has been proposed a method of raising the heat at the axial ends and covering the amount of heat radiated from both ends. Specifically, a method is used in which the winding portion of the tungsten filament forming the halogen lamp is made longer from the center toward the end, or the density is increased.

FIG. 8 explains the operation of such a fixing device, and shows a cross section perpendicular to the axial direction of the rotating body. In FIG. 8, reference numeral 104 denotes a fixing rotator, which has an elastic layer 107 made of RTV silicone rubber on an aluminum cored bar 106, and has a structure capable of sufficiently releasing an unfixed image (toner) 112 after fixing. ing.

A heating halogen heater 108 is provided inside the fixing rotator 104, and the halogen heater 108 is controlled by a control circuit (not shown) based on the temperature detected by the thermistor 109. ing. Thus, the fixing rotator 104 is heated to a predetermined temperature. Reference numeral 105 denotes a pressing rotator which is pressed against the fixing rotator 104 and rotates together with the fixing rotator 104 in the direction of the arrow. Therefore, the unfixed image 1 formed on the recording material 111 by the well-known electrophotographic process technology
Reference numeral 12 denotes a recording material 111 which enters the fixing nip through the entry guide 110 and is heated and pressed in the fixing nip.
It will be fixed on the top.

FIG. 9 shows a cross section of the fixing rotating body 104 parallel to the axial direction. In FIG. 9, reference numeral 106 denotes a metal core, which is made of a uniform material from the central portion 114 to the end 115 of the recording material passage portion. An RTV silicone rubber layer 107 is adhered to the surface of the metal core 106, and the metal core is heated by radiation from the tungsten filament 113 of the halogen heater 108 disposed inside the metal core.

As shown in FIG. 9, the fixing rotating body 104 is supported at its axial end by a holding member 116.
The heat stored in the fixing rotator 104 flows toward the holding member 116 through the aluminum cored bar 106, and this heat loss contributes to lowering the surface temperature of the end 115 than the center 114. . Therefore, this end 11
In order to prevent the temperature from being lowered, the arrangement of the tungsten filaments 113 is closer to the end.

Some conventional fixing devices use a temperature control device to maintain the surface temperature of a fixing rotating body at a predetermined value. Hereinafter, such a fixing device will be described with reference to FIG. As shown in FIG. 17, the fixing device includes a rotatable fixing roller 211 serving as a fixing rotator, a pressure roller 212 serving as a pressing rotator rotating while pressing against the fixing roller 211, and a fixing roller 211. A detachable coating device 213 for supplying a release agent to the surface;
11 and a cleaning web 214 for cleaning toner or paper powder as a developer adhering to the surface of the pressure roller 212.

The fixing roller 211 has a structure in which a surface of a metal pipe is covered with silicone and fluorine rubber. The pressure roller 212 is formed by providing silicone on the surface of a metal roller and applying a fluororesin coat on the surface. Inside the fixing roller 211 and the pressure roller 212, a heater 216 such as a halogen lamp is disposed as a heating unit. The pressure roller 212 is in contact with a thermistor 215 serving as a temperature detecting means, and is connected to a heater 21 via a temperature adjusting circuit (not shown) serving as a temperature controlling means.
By controlling the voltage to 6, the surface temperature of the roller is adjusted. The rollers 211 and 212 are rotatably supported in a direction indicated by an arrow with respect to a printer main body (not shown).

The coating device 213 includes a release agent tank 213a containing silicone oil as a release agent, and a release agent tank 213.
a pumping roller 213b for pumping the release agent from a.
Roller 213c for applying release agent to fixing roller 211
And a blade 213d for controlling the application amount of the release agent
It is composed of The application roller 213c is rotatably disposed by covering a surface of sponge rubber with silicone rubber, and is disposed detachably on the fixing roller 211, and applies a release agent to the fixing roller 211. . The application amount of the release agent is adjusted by the blade 213d and is applied at a constant application amount from the front end to the rear end of the recording material (not shown).

The cleaning web 214 has a nickel web 214a pressed against the fixing roller 211 side and a Nomex felt 214b pressed against the pressure roller 212 side.
The roller is being cleaned.

In this state, when the recording material is conveyed, the fixing roller 211 and the pressure roller 212 rotate at a constant speed, and when the recording material passes between the rollers 211 and 212, the recording material is substantially constant from both the front and back surfaces. Pressurization and heating are performed at the pressure temperature, so that the unfixed toner carried on the surface is melted.

Therefore, in order to obtain a good image, it is necessary to maintain the surface temperature of the roller at a predetermined temperature.
Predetermined temperature control is performed by the above-described temperature control device.

Further, there is a conventional fixing device in which the thickness of the fixing roller is reduced. Hereinafter, such a fixing device will be described with reference to FIGS. As described above, in an image forming apparatus employing an electrophotographic method, a heat fixing method is often used as a method for fixing an unfixed developer image on a sheet as a recording material. One factor that determines the performance of the fixing device that performs this heat fixing is the thickness of the fixing roller.

The fixing roller is usually made of an aluminum or iron-based metal material. If the thickness of the fixing roller is reduced, the volume of the fixing roller at that time, that is, the heat capacity is reduced. Disadvantages are known to occur.

Advantages include a short warm-up time and low roller material costs. A disadvantage is that the temperature rise in the non-sheet passing portion is large, and as a result, the roller and its peripheral portion are thermally damaged.

That is, the heat capacity decreases as the thickness decreases. Therefore, there is an advantage that the warm-up time is shortened. That is, the time required for the temperature of the fixing roller surface to change from room temperature to the temperature regulation temperature is shortened. On the other hand, there is a disadvantage in that the temperature change due to the paper passing is large, so that the temperature rise in the non-paper passing portion becomes large. Conventionally, when the copy speed (that is, the speed at which heat is removed from the fixing roller) is determined from these balances, the thickness of the fixing roller is almost determined.

However, in recent years, there has been an increasing demand from users for shortening the warm-up time for OA equipment, and it has become necessary to prevent the temperature rise in the non-sheet passing portion and to make the core metal thinner.
A heat fixing device as shown in FIG. 23 has been proposed. FIG. 23 is a sectional view of a fixing roller in a copying machine having a copy speed of 30 sheets / min (hereinafter referred to as cpm). The both ends of the aluminum fixing roller 301 are insulated bearings 332.
a, 332b and bearings 333a, 333b, are supported by the front and rear side plates 334a, 334b of the fixing unit. The fixing roller 301 has halogen heaters 335 and 336 as heat supply means, and the two heaters have light distribution characteristics shown in FIG. Therefore, any one heater suitable for the paper size can be selected and used by the detection signal of the paper size detection means (not shown) provided in the copying machine main body, and the surface temperature of the fixing roller 301 can be selected. Is 180 ° C based on temperature detection by thermistor 339
The temperature is adjusted to For example, large-size paper (A3, B4,
When almost the entire area of the fixing roller 301 is a sheet passing portion as in the case of A4 width, heat is supplied to almost the entire area using the halogen heater 335, and small-size paper (A4 length, B5, B5
If there are many non-paper passing parts as in (vertical), halogen heater 3
The amount of heat applied to the non-sheet passing portion is greatly reduced by using No. 36. Conventionally, the thickness of the fixing roller had to be 6 mm or more in order to suppress the temperature rise in the non-sheet passing portion to within 230 ° C. However, according to the above method, the thickness could be reduced to 1 mm. As a result, the warm-up time can be reduced and the cost can be significantly reduced.

Next, another conventional example will be described. Conventionally, image forming apparatuses such as electrophotographic copying apparatuses include:
A fixing device using a heat roller system is used. As a fixing device based on the heat roller method, a fixing roller, a pressure roller rotatably pressed against the fixing roller, and forming a nip portion for pressing and conveying the transfer material in cooperation with the fixing roller; A halogen lamp which extends coaxially with the axis of the fixing roller and which is a heater for heating the surface of the fixing roller to a predetermined temperature, wherein the halogen lamps are arranged at intervals along the axis. Some have a plurality of filament portions made of tungsten.

When the surface of the fixing roller is heated by a halogen lamp inside the fixing roller, heat is dissipated from the end of the fixing roller to the outside. Therefore, it is difficult to maintain a uniform surface temperature distribution of the fixing roller.

Therefore, in order to keep the surface temperature of the fixing roller uniform, each filament located near the end of the halogen lamp is made longer than the filament located at the center of the halogen lamp, and the light distribution at the end of the halogen lamp is increased. A method has been proposed in which the amount of heat dissipated from the end of the fixing roller is compensated for by making the intensity of light distribution higher than the light distribution at the center of the halogen lamp.

Halogen lamp 407b according to this method
Are arranged at intervals along the axis of the fixing roller 401, as shown in FIG. 30, and a plurality of filament portions 421, 422, 423, 424, and 4 made of tungsten.
25, 426, 427, and 428.

The filament section 421 includes a fixing roller 401
And the number is 1. On one side of the filament portion 421, each filament portion 422, 42
3, 424, 425, 426, and 427 are arranged toward one end of the fixing roller 401 at a fixed interval from each other. On the other side of the filament part 421, like the one side of the filament part 421, each filament part 422, 423, 424, 425, 426, 427
Are arranged at regular intervals toward the other end of the fixing roller 401. Each filament part 42
1, 422, 423, 424, 425, 426 have the same length dimension L1. Each filament part 427, 428
Have the same length L2, and the length L2 of the filament portion 427 is different from the length L1 of the filament portion 421. Note that each of the length dimensions L1 and L2 is
01 is selected such that the surface temperature distribution becomes uniform. Specifically, the length L1 is 16 mm, and the length L2 is 25 mm. The distance between the filament portions is 6 mm.

As another method for maintaining a uniform surface temperature distribution, the arrangement interval of each filament portion in the vicinity of the end of the halogen lamp is made smaller than the arrangement interval of each filament portion in the center portion of the halogen lamp. Is made stronger than the light distribution at the center of the halogen lamp to compensate for the amount of heat dissipated from the end of the fixing roller.

Halogen lamp 407 according to another method
As shown in FIG. 31, c is a plurality of filament portions 441, 442, 443, 444, which are arranged at intervals along the axis of the fixing roller 401 and are made of tungsten.
445, 446.

The filament section 441 includes a fixing roller 401
And the number is 1. On one side of the filament portion 441, each filament portion 442, 44
3, 444, 445 and 446 are arranged at an interval from each other toward one end of the fixing roller 401. On the other side of the filament portion 441, the filament portion 4
41, each filament section 442, 4
43, 444, 445, 446 are arranged at an interval from each other toward the other end of the fixing roller 401.
In addition, each filament part 442,443,444,44
5,446 have the same length dimension.

The filament part 441 and the filament part 4
F, the distance between the filament 442 and the filament 443 is G, the distance between the filament 443 and the filament 444 is H, and the distance between the filament 442 and the filament 444 is H.
If the distance between the filament part 445 and the filament part 445 is I, and the distance between the filament part 445 and the filament part 446 is I,
The following relational expression F = G> H = I = J is satisfied. Specifically, the intervals F and G are 10 mm, and the intervals H, I and J are 6 mm.

Next, a conventional electrophotographic apparatus for forming a color image will be described with reference to FIG.

The color electrophotographic apparatus shown in FIG.
A transfer material transport system I provided from the right side of the apparatus main body 501 to a substantially central portion of the apparatus main body, and a transfer drum 515 constituting the transfer material transport system I at a substantially central portion of the apparatus main body 501. The latent image forming section II is roughly divided into a latent image forming section II and a developing means disposed in close proximity to the latent image forming section II, that is, a rotary developing device III.

The transfer material transport system I has the following configuration. First, an opening is formed in the right wall of the apparatus main body 501, and detachable transfer material supply trays 502 and 503 are provided in the opening so as to partially protrude outside the apparatus. Paper feed rollers 504 and 505 are disposed almost directly above the trays 502 and 503, and a transfer drum serving as a transfer means rotatable in the direction of arrow RA disposed to the left of the paper feed rollers 504 and 505. A paper feed roller 506 and paper feed guides 507 and 508 are provided so as to communicate with 515. In the vicinity of the outer peripheral surface of the transfer drum 515, the contact roller 50 moves from the upstream side to the downstream side in the rotation direction.
9, a gripper 510, a transfer material separating charger 511, and a separating claw 512 are sequentially arranged. A transfer charger 513 and a transfer material separating charger 514 are provided on the inner peripheral side of the transfer drum 515. The transfer drum 515 has a transfer sheet (not shown) made of polyvinylidene fluoride or the like adhered to a portion where the transfer material is wound, and the transfer material is electrostatically adhered onto the transfer sheet. It has become. At the upper right side of the transfer drum 515, a conveyor belt 516 is provided in proximity to the separation claw 512, and a fixing device 518 is provided at the end (right) end of the conveyor belt 516 in the transfer material conveyance direction (right). . Further downstream of the fixing device 518, the discharge tray 5 extends outside the apparatus main body 501 and is detachable from the apparatus main body 501.
17 are provided.

Next, the configuration of the latent image forming section II will be described. First, the photosensitive drum 519 as a latent image carrier rotatable in the direction of arrow RB in FIG.
5 is provided in contact with the outer peripheral surface. Above the photosensitive drum 519 and near its outer peripheral surface, the photosensitive drum 51
9 from the upstream to the downstream in the rotation direction of the charger 9
20, a cleaning unit 521 and a primary charger 523 are sequentially arranged, and further, an image exposure unit 524 such as a laser beam scanner for forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum 519, and an image such as a mirror. Exposure reflection means 525 is provided.

Finally, the structure of the rotary developing device III is as follows. A rotatable housing (hereinafter referred to as a “rotating body”) 526 is disposed at a position facing the outer peripheral surface of the photosensitive drum 519, and four types of developing devices are provided in the rotating body 526 at four positions in the circumferential direction. The electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 519 is visualized (that is, developed). The four types of developing devices are a yellow developing device 527Y, a magenta developing device 527M, a cyan developing device 527C, and a black developing device 527BK, respectively.

First, the sequence of the entire image forming apparatus having the above-described configuration will be briefly described, taking the case of the full-color mode as an example. When the above-described photosensitive drum 519 rotates in the direction of arrow RB in FIG.
The upper photoconductor is uniformly charged by the primary charger 523. In the apparatus shown in FIG. 35, the operation speed of each part (hereinafter referred to as process speed) is 160 mm / sec. When the photosensitive member is uniformly charged by the primary charger 523, image exposure is performed by the laser beam EL modulated by the yellow image signal of the document 528, and an electrostatic latent image is formed on the photosensitive drum 519. By the rotation of the rotating body 526, the electrostatic latent image is developed by the yellow developing device 527Y fixed at the developing position in advance.

On the other hand, the paper feed guide 507 and the paper feed roller 50
6. The transfer material conveyed via the paper feed guide 508 is held by the gripper 510 at a predetermined timing, and is electrostatically moved by the contact roller 509 and the electrode facing the contact roller 509. Is wound around the transfer drum 515. The transfer drum 515 includes a photosensitive drum 519.
35, the visible image developed by the yellow developing device 527Y is located at a position where the outer peripheral surface of the photosensitive drum 519 and the outer peripheral surface of the transfer drum 515 are in contact with each other. The image is transferred by the transfer charger 513. The transfer drum 515 continues to rotate as it is,
Prepare for the transfer of the next color (magenta in FIG. 35).

On the other hand, the photosensitive drum 519 is neutralized by the neutralizing charger 520, is cleaned by a cleaning means 521 using a conventionally known blade method, is charged again by the primary charger 523, and is charged by the next magenta image signal. Image exposure. The rotary developing device rotates while an electrostatic latent image based on a magenta image signal is formed on the photosensitive drum 519 by the image exposure, and fixes the magenta developing device 527M to the above-described predetermined developing position, thereby setting a predetermined position. Perform magenta development. Subsequently, the above-described process is performed for the cyan and black colors, respectively, and when the transfer of the four colors is completed, the four-color image formed on the transfer material is transferred to each charger 5.
20, 514, the gripping of the transfer material by the gripper 510 is released, and the transfer material is separated from the transfer drum 515 by the separation claw 512, sent to the fixing device 518 by the transport belt 516, and heat and A series of full-color print sequences are fixed by pressure and a required full-color print image is formed.

At this time, the fixing operation speed of the fixing device 518 is 90 mm / sec, which is lower than the main body process speed of 160 mm / sec. This is because a sufficient amount of heat must be applied to the toner when melting and mixing unfixed images on which two to four layers of toner are stacked as described below. As a result, the amount of heat applied to the toner is increased.

As described above, since a multicolor toner forms two to four layers of a multicolor toner in a color image, the electrophotographic apparatus for forming a color image has the following two points for black and white. It has different features from the device.

The first feature relates to the toner used.

As the toner, a sharp-melting toner is used. By using a sharp melt toner, the color reproduction range of a copy can be widened and a color copy faithful to a multicolor or full-color image of a document can be obtained.

Such a sharp melt toner includes, for example, a binder resin such as a polyester resin or a styrene-acryl ester resin, a colorant (a dye, a sublimable dye),
It is manufactured by melt-kneading, pulverizing, and classifying a toner-forming material such as a charge control agent. If necessary, an external addition step of adding various external additives (for example, hydrophobic colloidal silica) to the toner may be added. As such a color toner, a toner using a polyester resin as the binder resin is particularly preferable in consideration of the fixing property and the sharp melt property. Examples of the sharp-melt polyester resin include a polymer compound having an ester bond in the main chain of a molecule synthesized from a diol compound and a dicarboxylic acid.

In particular, the following equation

[0043]

Embedded image (Wherein R is an ethylene or propylene group, x, y
Is a positive integer of 1 or more, respectively, and the average value of x + y is 2 to 10. A) a bisphenol derivative or a substituted product thereof as a diol component, and a carboxylic acid component comprising a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, Phthalic acid, terephthalic acid,
A polyester resin obtained by co-condensation polymerization with at least trimellitic acid and pyromellitic acid) is more preferable because it has sharp melting characteristics.

The softening point of the polyester resin is 75 to 15
0 ° C, preferably 80 to 120 ° C.

FIG. 36 shows an example of the softening characteristics of a sharp melt toner containing this polyester resin as a binder resin. The measurement conditions are as follows.

Using a flow tester CFT-500A type (manufactured by Shimadzu Corporation), a die (nozzle) diameter of 0.2 mm,
A plunger drop-temperature curve of toner drawn when the temperature is increased at a constant speed of 6 ° C./min after a preheating time of 300 seconds at an initial set temperature of 70 ° C. and a preload time of 300 seconds by applying a 20 kg extrusion load with a thickness of 1.0 mm (Hereinafter referred to as a softening S-shaped curve). The toner used as the sample is a fine powder precisely weighed from 1 to 3 g, and the cross-sectional area of the plunger is 1.0 cm ² . The softening S-shaped curve is as shown in FIG. As the temperature rises at a constant speed, the toner is gradually heated and starts to flow out (plunger fall PA → PB). When the temperature is further increased, the toner in a molten state flows out greatly (PB → PC → PD), stops descending the plunger, and ends (PD → PE).

The height h of the S-shaped curve indicates the total amount of outflow, and h /
The temperature T ₀ corresponding to the PC point 2 indicates the softening point of the toner.

Whether or not the toner and the binder resin have sharp meltability can be determined by measuring the apparent melt viscosity of the toner or the binder resin.

The toner or binder resin having such a sharp melt property is defined as T ₁ when the apparent melt viscosity is 10 ³ poise and T ₂ when the apparent melt viscosity is 5 × 10 ² poise. _{when, T 1 = 90~150 ℃ | △} T | = | T 1 -T 2 | = refers to satisfy the condition of 5 to 20 ° C..

The sharp-melt resin having these temperature-melt viscosity characteristics is characterized in that the viscosity is sharply reduced by heating. Such a decrease in viscosity causes appropriate mixing between the uppermost toner layer and the lowermost toner layer, and furthermore, the transparency of the toner layer itself is sharply increased, and good color reduction mixing is caused.

Such a sharp-melting color toner also has a property of having a high affinity and being easily offset to the fixing roller.

Therefore, in the fixing device of the image forming apparatus using the above color toner, it is necessary to exhibit high releasability over a long period of time. Hereinafter, a fixing device 518 which is a second feature of the electrophotographic apparatus for forming a color image will be described with reference to FIG.

In FIG. 37, a fixing roller 529 serving as a fixing means has an HTV (high-temperature vulcanization type) silicone rubber layer 532 on an aluminum cored bar 531 and an RTV (outside thereof) on the outside thereof.
Room temperature vulcanization type) Silicone rubber layer 533, thickness 3m
m, 40 mm in diameter.

On the other hand, a pressing roller 530 serving as a pressing means is provided with an HTV having a thickness of 1 mm on an aluminum core bar 534 and a fluororesin layer 535 on the surface thereof.
It has become.

The fixing roller 529 is provided with a halogen heater 536 which is a heating means, and the pressure roller 530 is also provided with a heater 537 in a metal core for heating from both sides. The temperature of the pressure roller is detected by the thermistor 538 in contact with the pressure roller 530, and the halogen heaters 536 and 537 are controlled by the control device 539 based on the detected temperature, and the temperature of the fixing roller 529 and the temperature of the pressure roller 530 are detected. Both temperatures are controlled to be kept constant at about 170 ° C. The fixing roller 529 and the pressing roller 530 are pressed by a pressing mechanism (not shown) with a total pressure of about 40 kg.

In FIG. 37, O is an oil application device serving as a release agent application device, CL is a cleaning device, and CB is a cleaning blade for removing oil and dirt from the pressure roller. The oil applicator O is a dimethyl silicone oil 541 (KF96 manufactured by Shin-Etsu Chemical Co., Ltd.) in an oil pan 540.
300 cs) is passed through the oil pumping roller 542 and the oil application roller 543, and the oil application amount is regulated by the oil application amount adjusting blade 544 to apply the oil onto the fixing roller 529. In the apparatus shown in FIG. 37, an amount of 0.08 g / A4 is applied as a coating amount by a measuring method described later.

The amount of silicone oil applied by the oil application device O is determined as follows.

First, the weight of 50 sheets of A4 size blank paper is
₁ g, without transferring the image onto this blank paper and without applying silicone oil to the rubber layer of the fixing roller.
Blank paper 50 after passing between the fixing roller and the pressure roller
Let the weight of the sheet be B ₁ (g). Next, similarly, the weight of another 50 sheets of A4 size paper is set to A ₂ (g), and the image is not transferred onto this white paper, but the silicone oil is applied to the rubber layer of the fixing roller. The weight of 50 blank sheets after passing between the fixing roller and the pressure roller is C ₁ (g).
And Using the above A ₁ , B ₁ , A ₂ , and C ₁ , the amount of silicone oil applied per sheet of A4 size white paper X
(G) is obtained by the following equation.

X = (C ₁ + A ₁ -B ₁ -A ₂ ) / 50 On the other hand, the cleaning device CL is Nomex (trade name).
The nonwoven fabric web 546 is pressed against the fixing roller 529 by the pressing roller 545 for cleaning. The web 546 is appropriately wound by a winding device (not shown) so that toner and the like do not accumulate on the contact portion.

The above-described electrophotographic apparatus for forming a color image forms a visible image only on one side, and an apparatus capable of forming this visible image on both the front surface and the back surface of a transfer material has already been proposed. I have. Hereinafter, the device will be described with reference to FIG.

The apparatus shown in FIG. 38 is an electrophotographic apparatus for forming a color image similarly to the conventional apparatus shown in FIG. 35, except that an image can be formed on both sides of a transfer material. Hereinafter, a mechanism for forming a two-sided image will be described. The same reference numerals are given to the same parts as those in the above-described apparatus, and the description will be omitted.

The present apparatus is provided with a re-feed roller 560 as a transport mechanism for double-sided image formation and a transport path 561.

Below the discharge roller 562, a re-feed roller 560 for feeding the transfer material once placed on the discharge tray 517 to the latent image forming section II is provided. Behind the re-feed roller 560, A transfer path 561 for transferring the transfer material is provided.

Next, the operation of the apparatus of the present invention for making a two-sided copy of a color image will be described.

The transfer material developed in the developing device III and carrying the unfixed toner image on the surface thereof is conveyed by a conveying belt unit 516.
Roller 529 and pressure roller 530
After the image is fixed, the sheet is brought to the sheet discharge tray 517 by the sheet discharge roller 562. Thereafter, the re-feed roller 56
0, the sheet is fed again, passes through the conveyance path 561, is conveyed again to the latent image forming section II, and forms a color image on the back side in the same manner as the front side. In this way, the transfer material having the color image already fixed on the front surface and carrying the unfixed color toner image transferred on the rear surface is conveyed to the fixing roller 529 and the pressure roller 530 by the conveyor belt means 516.

As described above, according to the conventional apparatus shown in FIG. 38, a color image could be formed on both sides of the transfer material.

The fixing device of the electrophotographic apparatus capable of copying a color image on both sides in this manner has substantially the same configuration as that of the above-described electrophotographic apparatus for single-sided copying shown in FIG. 37, but as shown in FIG. The material of the surface layer of the pressure roller is different. In the case of the apparatus shown in FIG. 39, since the color toner which is easily offset is carried on both sides of the paper, the surface layer of the pressure roller 530 'is made of RTV silicone rubber 533' instead of the conventional fluororesin 535 (hereinafter referred to as RTV silicone rubber 533 '). This type of fixing device is a fixing device for double-sided fixing).

This is because when the material of the surface layer of the pressure roller 530 ′ is a fluororesin, the toner image once fixed on the transfer material is offset to the surface layer of the pressure roller 530 ′ when heated again. This is because The reason why the offset does not occur when the RTV silicone rubber 533 'is used is as follows.
Although not clear, the pressure roller 53 has a good affinity and oil absorbency between the release oil and the RTV silicone rubber.
It is considered that because the oil is favorably retained on the surface layer of 3 ′, higher releasability can be obtained than with a fluororesin that repels oil easily.

However, as shown in FIG. 39, in the fixing device for double-sided fixing using silicone rubber as the material of the surface layer of the pressure roller, the durability is reduced by about 2 The limit was to hold 10,000 copies for a period of about one year, and regular maintenance was required.

On the other hand, in the case where only one-sided copying is performed, as shown in FIG. 37, the surface of the pressure roller is formed of a fluororesin (hereinafter, this type of fixing device is referred to as a one-sided fixing device). ) Can be used, and it is possible to extend the life of about 100,000 sheets in terms of the number of transfer materials and about 5 years in terms of period.

[0071]

However, each of the above-mentioned prior arts has the following problems.

First, in the conventional example shown in FIGS. 8 and 9, even if the distribution of the light distribution at the end portion is increased by adjusting the arrangement of the tungsten filament 113, the end portion in the axial direction of the rotating body is not required. Temperature tends to be lower than that in the central portion, and there is a problem that a fixing failure occurs during continuous paper feeding. In addition, when an extreme filament arrangement was adopted such that the temperature at the axial end was substantially the same as that at the center, the heater wattage was wasted to the axial end, and the same wattage heater was used. Even in this case, the thermal efficiency deteriorates, so the supply of heat to the rollers is delayed,
There is also a problem that the rise time of the fixing device becomes long. As described above, it has been difficult to solve the temperature drop at the axial end portion only by adjusting the light distribution characteristics.

Further, according to the conventional example shown in FIG. 17, since the heat from the heater 216 is supplied to the entire surface in the longitudinal direction of the roller, the recording having a small width in the longitudinal direction of the roller such as A4R or B5R. When fixing a recording material (hereinafter, a small-sized recording material) continuously, a problem occurs.

FIG. 18 shows a temperature change on the surface of the fixing roller 211 when a small-sized recording material is continuously conveyed. The polygonal line indicates the paper passing area, the top of each peak indicates the top of one recording material, and the bottom of each peak indicates the fixing roller surface temperature when the rear end of one recording material passes. I have. The solid line indicates a temperature change in the non-sheet passing area.

That is, when a small-sized recording material is continuously conveyed, heat is taken by the recording material, and the roller surface temperature in the paper passing area decreases. 216 is lit, but in the non-sheet passing area, the heat is not deprived by the recording material.
The roller surface temperature does not decrease. However, since the heater 216 is turned on, the roller surface temperature in the non-sheet passing area becomes
It will rise further. This hastened the deterioration of the rubber in the temperature rising portion of the roller.

Further, the image quality sometimes differs due to the temperature difference between the sheet passing area and the non-sheet passing area. Particularly, when a recording material having a size substantially equal to the width in the longitudinal direction of the roller (hereinafter, referred to as a large-size recording material) is fixed after continuous feeding of a small-size recording material, a non-printing area is determined. Fixing properties, glossiness, etc., differed depending on the temperature difference from the paper passing area. In particular, it was noticeable in the case of color image formation.

In order to solve these problems, light distribution has been given to the heater characteristics until now, but it has not been possible to completely suppress the temperature rise in the non-sheet passing area.

Further, in the conventional example shown in FIG. 23, if the fixing roller is made thinner in order to shorten the warm-up time and save the material of the fixing roller, the temperature rise in the non-sheet passing portion becomes higher. There was a problem.

For this reason, the limit of the thickness of the fixing roller is as follows.
It was determined by the limit of this temperature rise, and it could not be unnecessarily thinned. Further, according to the two-heater system as in the conventional example, the effect is great, but complicating the structure and increasing the cost are unavoidable, and when a small-diameter fixing roller is used, it cannot be realized due to space restrictions. There was something. In addition, there was also an absurdity that a large amount of heat was supplied to a non-paper passing portion that did not require heat supply.

According to the conventional apparatus shown in FIG.
The length L2 of the filament portions 427 and 428 located at the end is determined by the halogen lamp 407b.
21, 422, 423, 424, 425, 426, the filament part 42 is larger than the length L1.
7, 428 are output from the other filament portions 421, 42.
2, 423, 424, 425, and 426, the supply of heat to the fixing roller 401 is delayed, and the rising time until the surface temperature of the fixing roller 401 reaches the fixing temperature becomes longer.

Further, the halogen lamp 40 shown in FIG.
In FIG. 7c, the distances H,
Since I and J are larger than the distances F and G between the other filament portions, the output at the end portion is larger than the output at the central portion. Therefore, the supply of heat to the fixing roller 401 is delayed, and the surface temperature of the fixing roller 401 becomes lower than the fixing temperature. Rise time to reach.

Therefore, any of the halogen lamps 407
Also in b and 407c, the surface temperature of the fixing roller 401 cannot be raised to a predetermined fixing temperature until the next transfer material is introduced into the nip portion during continuous paper passing, and fixing defects are likely to occur. .

Further, in the conventional double-sided copying machine shown in FIG. 38, not only the double-sided copy but also the single-sided copy is frequently performed, but the pressure roller is considered in consideration of the case where the double-sided copy is performed. Therefore, a fixing device using RTV silicone rubber as the material of the surface layer had to be adopted, and frequent maintenance and replacement work had to be performed.

As a countermeasure, it has been considered that a fixing device for one-sided fixing is prepared so as to be replaceable and the user can select and use the device at any time. Was.

Further, an image forming apparatus capable of appropriately selecting the degree of gloss in an image after fixing is desired due to recent needs for various electrophotographic apparatuses. However, as described above, one type of fixing apparatus is used. In a conventional image forming apparatus using only the apparatus, such a demand cannot be satisfied.

The first object of the present invention is to solve the above-mentioned problems. The first object of the present invention is to provide a rotating body having a heating means inside, in which the temperature distribution in the axial direction is uniform and the start-up of the fixing device is started. An object of the present invention is to provide a fixing device capable of reducing time.

[0087]

[0088] The second object to the next, even the roller enclosing a heating means such as the fixing roller in a case where it is thinned, the non-paper passing area without causing unnecessarily heated, the wasted energy It is an object of the present invention to provide a fixing device that does not consume.

A third object is to provide a fixing device capable of uniformly and quickly raising the surface temperature of a rotating body such as a fixing roller to a predetermined fixing temperature.

The fourth object is that, in various fixing environments such as double-side fixing or single-side fixing, and further, to increase the gloss of an image, a fixing device most suitable for each environment can be used at any time. An object of the present invention is to provide an image forming apparatus capable of preventing a fixing failure due to mounting.

[0091]

According to the first invention of the present application,
The above object is provided with a rotating body pair including a fixing rotating body and a pressing rotating body having an elastic layer on a cored bar, and a heating unit disposed inside at least one of the rotating bodies of the rotating body pair. In the fixing device, the core of the rotator provided with the heating means is provided between the end of the rotator to which a supporting member or a driving member of the rotator is attached and a recording material passing portion of the rotator. , A thermal barrier material having a lower thermal conductivity than the core metal is inserted, and the thermal barrier material has a lower thermal conductivity.
λ, the thickness of the thermal barrier in the axial direction of the rotating body is t,
Assuming that the thermal conductivity is λ ₀ and the thickness of the end of the core metal is r ₀ , 1
This is achieved by being set so as to satisfy the expression of 00 × λ / t ≦ λ ₀ / r ₀ .

[0092]

[0093] in the following, according to the present second invention, the above object is a fixing rotary member having a heating means, for the fixing
The recording material is transported and fixed based on the axial end of the rotating body.
In the fixing device, air is blown outside the fixing rotating body.
Feed from the non-paper passing reference side in the axial direction to the paper passing reference side
This is achieved by having a blowing means .

According to the third aspect of the present invention, the above object is achieved by a pair of rotating bodies which rotate while being pressed against each other to form a nip for cooperating and conveying a transfer material.
A halogen lamp for heating a surface of the rotating body, wherein the halogen lamp is arranged at a central portion of the rotating body. A first filament group, a second filament group disposed on one side of the first filament group, and a third filament disposed on the other side of the first filament group And the first filament group comprises a plurality of filament portions arranged along the axis of the rotating body at an interval from each other, and the second filament group is The first filament group includes a plurality of filament portions arranged along one axis of the rotating body from one side of the first filament group to one end of the rotating body. The group comprises a plurality of filament portions arranged along the axis of the rotating body from the other side of the first filament group to the other end of the rotating body at an interval from each other, Each of the filament portions arranged from the central portion of the rotating body in the first filament group and the second filament group to one end thereof, and the first filament group and the third filament Each of the filament portions arranged from the central portion of the rotating body in the group toward the other end is arranged symmetrically with respect to the central portion of the rotating body, and constitutes the second filament group. The length of each filament and the length of each filament constituting the third filament group are gradually increased in the order of arrangement from the center to the end of the rotating body. It is achieved by increases.

Further, according to the fourth invention of the present application, the above object is achieved by a pair of rotating bodies that rotate while being pressed against each other and form a nip portion for cooperating and conveying a transfer material.
A halogen lamp for heating a surface of the rotating body, wherein the halogen lamp is arranged at a central portion of the rotating body. A first filament group, a second filament group disposed on one side of the first filament group, and a third filament disposed on the other side of the first filament group And the first filament group is composed of a plurality of filament portions arranged along the axis of the rotating body at an interval from each other, and the second filament group is The first filament group includes a plurality of filament portions arranged along one axis of the rotating body from one side of the first filament group to one end of the rotating body. The group comprises a plurality of filament portions arranged along the axis of the rotating body from the other side of the first filament group to the other end of the rotating body at an interval from each other, Each of the filament portions arranged in the first filament group and the second filament group from the center of the rotating body to one end thereof, and the first filament group and the third filament Each of the filament portions arranged from the central portion of the rotating body in the group toward the other end is arranged symmetrically with respect to the central portion of the rotating body, and constitutes the second filament group. The distance between the filaments and the distance between the filaments constituting the third filament group are gradually reduced in the order of arrangement from the center to the end of the rotating body. It is achieved by Rukoto.

According to the fifth invention of the present application, the above object is achieved by an image forming apparatus having a fixing device for fixing an unfixed image on a transfer material obtained by the operation of the image forming apparatus to form a permanent image. image image forming apparatus, the application of different fixing devices are the universal exchange at any time, provided with means for identifying each fixing device, according to the use of the identified fixing device
This is achieved by setting to perform an image forming operation .

[0097]

According to the first aspect of the present invention, the core metal of the fixing rotating body or the pressing rotating body having the heating element therein has the above-described thermal conductivity between the recording material passing portion and the axial end. A lower thermal barrier material is inserted compared to the cored bar. Therefore, even if heat is applied to the core by the heating element and heat is transferred from the recording material passage portion to the axial end, the heat conductivity of the heat shielding material is higher than that of the core. Is also low, preventing heat transfer to the axial end.

[0098]

[0099] in the following, according to the present second invention, the recording material is nipped and conveyed to the fixing rotary member and the pressurizing rotating body in the case of small-sized paper, the blowing means are driven by the drive control means. Therefore, unnecessary heat staying in the non-sheet passing area not in contact with the recording material is sent from the non-sheet passing reference side to the sheet passing reference side by the blowing means. As a result, not only is the temperature rise in the non-sheet passing area prevented, but also the heat contributes to the fixing operation in the sheet passing area, so that energy can be saved.

In the fixing device according to the third aspect of the present invention, the length of each filament constituting the second filament of the halogen lamp and the length of each filament constituting the third filament group are set. Gradually increases in the order of arrangement from the center of the rotating body toward the end thereof.

When a plurality of transfer materials are continuously fixed,
Each time the transfer material passes through the nip portion, the surface temperature of the rotating body is reduced entirely or partially, so the surface temperature of the rotating body is fixed at a predetermined temperature until the next transfer material is introduced into the nip portion. It is necessary to start up uniformly by the temperature. Since the length dimension of each filament portion of the second filament group and the third filament group is large in the order of arrangement from the center to the end of the rotating body, the amount of heat supplied from the halogen lamp to the rotating body is It becomes uniform in the axial direction of the rotating body.

Further, in the fixing device according to the fourth aspect of the present invention, the interval between the respective filament portions constituting the second filament group and the interval between the respective filament portions constituting the third filament group are set at the central portion of the rotating body. And gradually decreases in the order of arrangement toward the end.

The distance between the filaments constituting the second filament group and the distance between the filaments constituting the third filament group are small in the order of arrangement from the center to the end of the rotating body. The amount of heat supplied from the halogen lamp to the rotating body becomes uniform in the axial direction of the rotating body.

According to the fifth aspect of the present invention, since a plurality of fixing devices having different applications can be replaced at any time, a user or the like selects and mounts a fixing device suitable for a desired image. Then, the image forming apparatus identifies each fixing device by the identification unit and performs an image forming operation suitable for each of the fixing devices.
In addition, other inappropriate operations are prohibited. Thus,
According to the present invention, the most suitable fixing is reliably performed in various fixing environments.

[0105]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 10 of the present invention will be described with reference to the drawings.

<Embodiment 1> First, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view parallel to the axial direction of the fixing rotating body 100 of the present embodiment. In FIG. 1, reference numeral 100a denotes a metal core,
An RTV silicone rubber layer 100b is formed on Oa. Further, a heating element (not shown) such as a halogen lamp is provided in the fixing rotating body 100, and transmits heat to the core metal 100a and the rubber layer 100b.

However, the flow of heat in the rotating body mainly occurs in the core metal as shown by arrows in FIG. this is,
This is because the core metal has a higher thermal conductivity than the others. Aluminum is generally used as the material of the core metal. In this case, the thermal conductivity is 2.33 × 10 ² [J / m · sec.
.Degree. C.] and 3.81.times.10.sup.7 of RTV silicone rubber.
^-1 [J / m · sec · ° C], there is a difference of about 500 times in the ease of heat flow. Therefore, the amount of heat flowing to the holding portion at the end of the cored bar indicated by arrow Y in FIG. 2 cannot be ignored compared to the amount of heat transferred to the surface of the rotating body indicated by arrow Z, and lowers the surface temperature of the rotating body end. It is a factor.

Therefore, as shown in FIG. 1, the core material 100a in this embodiment is provided with the recording material passing portion 1 of the rotating body 100.
A heat-blocking material 101 is inserted between the recording material passing portion 102 and the end holding portion 103 to effectively suppress the transfer of heat between the recording material passing portion 102 and the end holding portion 103. As a result, it is possible to reduce the amount of heat radiated to the rotating body holding portion and prevent the surface temperature of the rotating body end from lowering.

Hereinafter, an experimental example in which the temperature distribution in the axial direction of a rotating body using four kinds of materials having different thermal conductivities as a heat insulating material and a conventional rotating body not using the thermal insulating material is compared. explain. First, the rotating body used in the experimental example is as follows. Rotating body a: a conventional fixing rotating body that does not use a heat insulating material. Rotating body b: the thermal conductivity of the core metal is 2.33 × 10
² [J / m · sec · ° C.]) A fixing rotator using a heat-blocking material that is one-tenth of that of the rotator. Rotating body for fixing Rotating body d: Rotating body for fixing using a heat-blocking material having a thermal conductivity of 1/1000 of the core metal Rotating body e: A heat-blocking material having a thermal conductivity of 1/10000 of the core metal Rotating body for fixing used Here, the same halogen heater was used in all of the rotating bodies a, b, c, d and e. The total wattage of the halogen heater is 100 V, 800 W, and the light distribution characteristics shown in FIG. 3 are used. Also, the structure of the rotating body itself was the same except that a heat insulating material was inserted at the end of the cored bar. Further, the thickness t in the axial direction of the heat insulating material 101 shown in FIG. 4 is set to be the same as the thickness r ₀ of the holding portion at the end of the cored bar.

FIG. 5 shows the axial distribution of the surface temperature after a certain period of time has passed since the heaters of the five types of rotating bodies a, b, c, d, and e were set at an initial temperature of 20 ° C. However, since both the shape of the rotating body and the axial distribution of the surface temperature are symmetrical with respect to the center of the rotating body, FIG. 5 shows only one side (right side of the plane of symmetry).

In FIG. 5, the curves A, B, C, D, and E show the axial distribution of the surface temperature in the paper passing portion of each rotating body. ,
These are the rotating bodies c, d, and e.

As shown in FIG. 5, generally, the surface temperature distribution of the rotating body in the paper passing area is higher toward the center and lower toward the end of the paper passing area. However, in the fixing rotating body, it is necessary to minimize such axial distribution of the surface temperature in order to make the fixing property uniform in the axial direction. In the case of the temperature distribution A, a difference of about 20 ° C. appears between the center part and the end part. The temperature distribution B is also about 20 ° C., the temperature distribution C is about 15 ° C., and the temperature distributions D and E are about 10 ° C.

FIG. 6 shows an axial temperature difference Δ for each embodiment.
TP is plotted. FIG. 6 shows that the thermal barrier material having a thermal conductivity of about 1/10 that of the core metal has no sufficient effect, and the effect of the present invention starts to appear from 1/100 or less. In particular, the effect is remarkable at a ratio of 1/1000 or less. However, 1/1000 and 1 / 10,000
The difference between the effects is smaller.

Therefore, in the conventional rotating body a and the rotating body b in which the thermal conductivity of the heat shield is substantially equal to the thermal conductivity of the cored bar,
There is no effect when the number of continuous paper passes is small, but when a large amount of continuous paper passes, a difference appears in the evaluation of fixability, gloss, and the like near the end of the paper passing area. On the other hand, such a phenomenon does not occur in the rotating bodies c, d, and e.

Further, if attention is paid to the rising speed of the rotating body surface temperature, for example, when the surface temperature is increased by using the same wattage heater, the surface temperature from the heater ON to a predetermined time is determined by the rotating speed according to the present invention. The body e is about 5 to 10% higher than the conventional rotating body a.

This means that the use of the fixing rotator according to the present invention not only has the effect of reducing the temperature difference between the center and the end of the sheet passing portion, but also reduces the rise time of the fixing device (copier). (The time from when the switch is turned on until the fixing device reaches a temperature at which fixing can be performed) can be shortened.

In the example described above, the thickness t of the heat shielding material shown in FIG. 4 was set to the same size as the thickness r ₀ of the cored bar holding portion. The case where the thickness t is changed will be described.

When one-dimensional heat transfer is considered, the thermal resistance during heat passage is inversely proportional to the thermal conductivity and proportional to the distance in the heat transfer direction. In the case of the present embodiment, the heat transfer form of the portion where the heat insulating material is inserted is very close to a one-dimensional heat transfer state.

FIG. 7 shows the temperature difference ΔT between the center and the end of the rotating body.
This shows the relationship between the thickness of the heat shielding material and the thermal conductivity when P is 15 ° C. as in the case of the rotating body c. In FIG. 7, the vertical axis indicates the thermal conductivity of the heat insulation material, and the horizontal axis indicates the distance in the heat transfer direction.

[0120] The marks 印 shown in FIG. 7 indicate the position of the rotating body c. According to FIG. 7, the thermal resistance (temperature difference Δ
When the value related to the value of TP is fixed, the thermal conductivity and the distance in the heat transfer direction are substantially proportional. That is, if the same temperature difference ΔTP is obtained by using a material having a thermal conductivity twice that of the case of the rotating body c, it is necessary to double the thickness t in the heat transfer direction.

This relationship holds not only for the temperature difference ΔTP of the rotating body c but also for all the temperature differences ΔTP described in this embodiment.

The following can be said by combining the above facts with the above-mentioned effects of the thermal conductivity of the thermal barrier on the surface temperature. That is, the value obtained by dividing the thermal conductivity λ of the heat insulating material by the thickness t in the heat transfer direction is 100 minutes of the value obtained by dividing the thermal conductivity λ ₀ of the core by the thickness r ₀ of the core holding portion. Is determined to be 1 or less, the effect of the present invention is remarkably obtained.

According to this rule, if the thermal conductivity of the heat shielding material is high, the same effect cannot be obtained unless the thickness t of the heat shielding material is increased to the same extent. When expressed by an equation, 100 × λ / t ≦ λ ₀ / r ₀ is obtained.

However, the wattage of the halogen heater does not need to be the one used in this embodiment.

Specific materials having the above-described properties include stainless steel, heat-resistant plastic materials, and various ceramic materials. When stainless steel is used as a thermal barrier, its thermal conductivity is 13 [J / m · sec.
° C], which is about 1/18 of that of aluminum, so that the thickness t of the thermal barrier material should be about 5.6 times r ₀ according to the above equation.

The reason why stainless steel is suitable as a heat insulating material is that it has good corrosion resistance, has sufficient rigidity, and is easy to be connected to a rotating body (by a screw or the like).

In the case of a heat-resistant plastic material, the thermal conductivity is 0.1 to 1.0 [J / m · sec · ° C.] and is about 200 to 2000 times lower than that of aluminum. The thickness when used as a barrier may be correspondingly thin. Advantages of using a heat-resistant plastic material as a heat-blocking material include easy molding and low cost. In addition, since the thermal conductivity is small, the thickness of the heat shielding material can be reduced, and the rigid weakness can be covered.

However, care must be taken because plastic materials generally have a low heat-resistant temperature. Among heat-resistant plastic materials, continuous heat-resistant temperature of 316 ° C or higher, heat deformation temperature of 482 ° C
As described above, a glass fiber-filled silicone resin having a heat conductivity of 0.31 [J / m · sec · ° C.] is suitable.

The ceramic material is also suitable as a heat insulating material because its thermal conductivity is as low as about 1/30 to 1/100 of that of aluminum. An advantage of the ceramic material is that it has high heat resistance.

<Embodiment 2> Next, Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 10 is a schematic view of a fixing device according to a second embodiment of the present invention. The same reference numerals are given to the same parts as those in the conventional example shown in FIG.

In FIG. 10, reference numeral 220 denotes a reflecting mirror which is provided so as to cover the periphery of the heater 216, and reflects heat from the heater 216. The reflection mirror 22
0 is movable in the roller longitudinal direction by the position changing device 230 shown in FIG. In such a state, for example, when the recording material of the maximum copy size is conveyed, the reflecting mirror 220 moves to the end position of the fixing roller 211 as shown in FIG. When the reflecting mirror is at a position as shown in FIG. 11, the heater 216 is turned on, and heat from the heater 216 is supplied to almost the entire paper passing area of the fixing roller 211.

Next, when a small-sized recording material is conveyed, the reflecting mirror 220 adjusts the width of the recording material according to FIG.
Then, as shown in FIG. FIG. 13 shows temperature changes in the sheet passing area and the non-sheet passing area on the surface of the fixing roller 211 when a small-sized recording material is continuously conveyed in such a state.

When the recording material is conveyed, the surface temperature of the paper passing area decreases, and when the thermistor 215 detects the temperature, the heater 216 is turned on. Heater 21
When 6 is turned on, in the area not covered by the reflecting mirror 220, the heat from the heater 216 reaches the inner surface of the fixing roller 211, and the temperature of the fixing roller surface gradually recovers.

On the other hand, in the area covered by the reflecting mirror 220, the heat from the heater 216 is reflected by the reflecting mirror 220 and does not reach the inner surface of the fixing roller 211. That is, since no heat is supplied from the heater in the non-sheet passing area, the surface temperature does not increase significantly but gradually decreases, and eventually becomes constant.

As described above, the reflection mirror is movably disposed around the heater inside the fixing roller, and the position of the reflection mirror is adjusted according to the size of the recording material. Temperature difference from the conventional device can be reduced.

<Embodiment 3> Next, Embodiment 3 of the present invention will be described with reference to FIG. The same parts as those in the second embodiment are denoted by the same reference numerals, and the description is omitted.

FIG. 14 is a schematic view of a reflecting mirror according to the third embodiment of the present invention. The reflecting mirror used in the present embodiment is such that a reflecting mirror 221a is provided with an inclination in a mold 221 having a small diameter on the end side of the fixing roller and a large diameter on the center side of the fixing roller on the opposite side. ing. This is disposed around the heater 216 in the same manner as in the second embodiment, and is moved to the position shown in FIG. 11 in the case of a large-size recording material, and to the position in FIG. 12 in accordance with the width of the small-size recording material. It is intended to be. By using the reflecting mirror 221a, as in the second embodiment, it is possible to suppress the temperature rise in the non-sheet passing area and to reduce the temperature difference from the sheet passing area. Further, by using the reflecting mirror having the configuration as in the present embodiment, the heat reflected by the reflecting mirror in the non-sheet passing area is reflected toward the center at an angle. As a result, the heat from the heater can be effectively used.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

FIG. 15 is a control diagram according to the fourth embodiment of the present invention. FIG. 15 shows an example in which the reflecting mirrors described in the third and fourth embodiments are used, and the positions of the reflecting mirrors are controlled so as to be switched every predetermined number of sheets during continuous copying. By switching the reflection position according to the size of the recording material as in the second and third embodiments, it is possible to suppress the temperature rise in the non-sheet passing area. However, for example, when performing continuous fixing of a small-sized recording material, the reflecting mirror is always located at a position as shown in FIG. No heat is supplied.
Therefore, as shown in FIG. 13, the temperature in the non-sheet passing area gradually decreased, and a slight temperature difference ΔTH occurred. Therefore, in the present embodiment, as shown in FIG. 15, a predetermined number is set, and the position of the reflecting mirror is switched to a position as shown in FIGS. 11 and 12 for each predetermined number. Then, in the non-sheet passing area, the case where heat is supplied and the case where heat is not supplied are alternated, and it is possible to control the temperature to the one shown in FIG. As described above, by switching the position of the reflecting mirror, it is possible to further reduce the temperature difference between the sheet passing portion and the non-sheet passing portion, and it is possible to obtain a greater effect than in the second and third embodiments. Was.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 19 is a diagram showing a schematic configuration of a fixing device of a 30 cpm copying machine according to Embodiment 5 of the present invention. In FIG. 19, reference numeral 301 denotes a fixing roller, which is attached to the frame 306 via bearings 309 at both ends. Further, the fixing roller 301 is a gear 3
04, and receives a driving force from a driving system (not shown) of the main body via the gear 305. Reference numeral 302 denotes a pressure roller made of silicone rubber, which is pressed against the fixing roller 301,
The fixing roller 301 is driven to rotate. 303 is a halogen heater. The halogen heater 303 is attached to the frame 306 via a heater support plate 307 so as to enter the inner diameter of the fixing roller 301, and supplies the fixing roller 301 with heat required for the fixing process. 31
Reference numeral 0 denotes a sirocco fan, which starts blowing when a paper size detection unit (not shown) of the main body detects a small-size paper passing (B5R, A4R, letter R, etc.). As a result, a predetermined amount of air is taken into the space SA formed by the guide plate 308 and the fixing roller 301 shown in FIG. 20 through the duct 311 and forms an airflow in the direction shown by the arrow in FIG.

Here, the blow of the sirocco fan 310 is as follows.
This is performed when small-size paper is passed, that is, when the temperature of the non-sheet passing portion is high. Due to this blowing, the air flow shown in FIG. 21 is formed, and the amount of heat moves as shown in FIG. An excess amount of heat in the non-sheet passing portion is carried to the sheet passing portion by an air flow and used for fixing the toner.

According to the present invention, the excess heat of the non-sheet passing portion is supplied to the sheet passing portion by the air flow, so that there is no more temperature difference than in the related art when the small size sheet is passed. For this reason, the temperature of the non-sheet passing portion is not easily increased.

Due to this effect, in order to suppress the temperature rise in the non-sheet passing portion to 230 ° C. in a copying machine of 30 cpm, a fixing roller thickness of 5 mm was conventionally required.
It improved at 0.7 mm. For this reason, the warm-up time at the time of starting the apparatus of the embodiment could be significantly reduced from 170 seconds in the related art to 40 seconds by the configuration of the present embodiment.

Further, since heat is supplied from the non-sheet passing portion to the sheet passing portion when the small-size sheet is passed, resources can be saved.

Embodiment 6 Next, Embodiment 6 of the present invention will be described with reference to FIG. The same parts as in the fifth embodiment are denoted by the same reference numerals, and the description is omitted.

FIG. 22 is a diagram showing a schematic configuration of a sixth embodiment of the present invention, which is a fixing device of a copying machine of 30 cpm.

In FIG. 22, reference numeral 301 denotes a fixing roller, which is attached to the frame 306 via bearings 309 at both ends. Further, the fixing roller 301 is
4, a driving force is received from a drive system (not shown) of the main body via the gear 305. Reference numeral 302 denotes a pressure roller made of silicone rubber, which is pressed against the fixing roller 301,
The fixing roller 301 is driven to rotate. 303 is a halogen heater. The halogen heater 303 is supported by a frame 306 via a heater branch plate 307 so as to enter the inner diameter of the fixing roller 301.
To supply the heat required for the fixing process. Reference numeral 312 denotes a small DC motor, which is supported by the frame 306. 313 are fins, both ends of which are supported by the frame 306 via bearings 314. Further, it is press-fitted so as to rotate coaxially with the output shaft of the DC motor 312. 315 is a metal duct, and the frame 30
6 is supported.

As described above, in the apparatus of this embodiment,
Fins 313 are contained in a space surrounded by the frame 306, the duct 308, and the fixing roller 301 (referred to as a space SB). Then, when power is supplied to the DC motor 312, the fins 313 rotate in the direction of the arrow in FIG. 22 to form an airflow in the direction as shown.

In the apparatus set as described above, the paper size detecting means (not shown) of the main body is used for the small size paper (A4 size).
R, B5R, Letter R, etc.)
The fins 313 are driven to generate the above airflow.

With this configuration, the same effects as in the fifth embodiment can be obtained. In both the fifth embodiment and the sixth embodiment, the air blowing means dedicated to the fixing device is provided. However, this is not always necessary, and the same applies even when air can be received from the air flow duct of the main body. Needless to say, the effect is obtained.

Embodiment 7 Next, Embodiment 7 of the present invention will be described with reference to the drawings. FIG. 25 is a structural view showing an embodiment of the fixing device of the present invention, and FIG. 26 is a longitudinal sectional view showing a fixing roller used in the fixing device of FIG.

As shown in FIG. 25, the fixing device includes a fixing roller 401 rotating in a predetermined direction, and a fixing roller 401.
And a pressure roller 402 that rotates while pressing against the fixing roller 401 and forms a nip portion for pressing and conveying the transfer material 410 in cooperation with the fixing roller 401.

The fixing roller 401 has a hollow metal core 403, and the outer peripheral surface of the metal core 403 is covered with a rubber layer 404 made of RTV silicone rubber. The pressure roller 402 has a metal core 405 made of an aluminum material.
Is covered with a resin layer 406 made of a PFA tube.

A halogen lamp 4 is provided inside the fixing roller 1.
07a is arranged. The halogen lamp 407a
As shown in FIG. 26, the fixing rollers 4 are spaced apart from each other.
01, and a plurality of filament portions 413, 414, 415, 416 made of tungsten.
417, 418, 419 and 420. The filament part 413 is located at the center of the fixing roller 401, and its number is one. On one side of the filament part 413,
Each filament part 414, 415, 416, 417, 4
18, 419, 420 are arranged toward one end of the fixing roller 401 at a fixed interval from each other. On the other side of the filament section 413, the filament section 4
13, each filament portion 414, 4
15, 416, 417, 418, 419, 420 are arranged at a fixed interval from each other toward the other end of the fixing roller 401. Each filament section 414, 415, arranged on one side of the filament section 414
416, 417, 418, 419, 420 and each filament section 414, 415, 416, 417, 418, 419, arranged on the other side of the filament section 413.
420 are arranged symmetrically with respect to the filament portion 413.

Each filament section 413, 414, 41
5, 416, 417, 418, 419 and 420 are represented by L13, L14, L15, L16, L17, L18,
Assuming L19 and L20, the following relational expression is satisfied.

L13 <L14 <L15 <L16 <L17
<L18 <L19 <L20 Each filament part 414,4
The intervals of 15, 416, 417, 418, 419, 420 are the same.

In this embodiment, L13 = 8 mm, L
14 = 9.7 mm, L15 = 11.9 mm, L16 = 1
4.5 mm, L17 = 17.7 mm, L18 = 21.6
mm, L19 = 26.4 mm, L20 = 32.2 mm, and each filament portion 414, 415, 416, 41
The distance between 7,418,419,420 is 6mm,
The ratio between the lengths of the filament portions adjacent to each other is preferably set to a value in the range of 1.1 to 1.3, and more preferably to a value in the range of 1.2 to 1.24.
Further, the interval between the filament portions does not need to be 6 mm, and may be a value between 0.1 and 2 times the length of the filament portion 413 located at the center.

The input voltage of the halogen lamp 407a is 10
0V and its output is 800W.

A temperature detecting element 408 is in contact with the surface of the fixing roller 401. The temperature detecting element 408 detects the surface temperature of the fixing roller 401, and the detected temperature is used for controlling the operation of the halogen lamp 407a.

An entrance guide 409 is provided at the entrance side of the nip formed between the fixing roller 401 and the pressure roller 402.
Are disposed, and an exit guide 412 is disposed on the exit side of the nip portion.

Before the fixing process for fixing the unfixed toner image 411 on the transfer material 410 is started, the fixing roller 401 is heated by the halogen lamp 407a, and the surface temperature of the fixing roller 401 is maintained at a predetermined fixing temperature.

After the surface temperature of the fixing roller 401 is maintained at the fixing temperature, the transfer material 410 is introduced into the nip while being guided by the entrance guide 409. In the nip
The toner image 411 on the transfer material 410 is heated and pressed.
After the transfer material 410 passes through the nip portion, the toner image 411 is fixed on the transfer material 410 as a permanent image.

The transfer material 410 on which the permanent image is formed is discharged outside while being guided by the exit guide 412.

When an image is continuously formed on a plurality of transfer materials 410, the surface temperature of the fixing roller 401 decreases every time the transfer material 410 passes through the nip portion. Fixing roller 401 before introduction
It is necessary to raise the surface temperature to a predetermined fixing temperature. However, since the length of each filament portion of the halogen lamp 407a is larger in the arrangement order from the center of the fixing roller 401 to the end of each filament portion, the halogen lamp Since the amount of heat from 407a is uniformly supplied to the fixing roller 401 in the axial direction, the rising time until the surface temperature of the fixing roller 401 reaches the fixing temperature is shortened,
The surface temperature of the fixing roller 401 can be raised to a predetermined fixing temperature before the next transfer material 410 is introduced into the nip portion, and the surface temperature distribution of the fixing roller 401 is made uniform again. As a result, the unfixed toe image 411 on the next transfer material 410 can be reliably fixed to the transfer material 410 without causing a fixing failure.

A test for confirming the above-described effects was performed, and the results are shown in FIG. In this test, when the surface temperature of the fixing roller 401 is 20 ° C., the heating operation by the target halogen lamp is started, and three minutes after the start of the heating operation, the surface temperature of the fixing roller 401 is measured, and the surface temperature distribution is shown by a curve. . In this test, halogen lamp 407 was used.
a, Conventional halogen lamp 407b (shown in FIG. 30)
And a halogen lamp 407f.

The halogen lamp 407f has each filament portion (not shown) in the same arrangement as the halogen lamp 407b. Each filament part 4 of the halogen lamp 407b
The length L1 of the filament portion corresponding to 21, 422, 423, 424, 425, 426 is 14 mm,
The length L2 of the filament portion corresponding to the filament portions 427 and 428 is 35 mm.

As shown in FIG. 29, the surface temperature distribution of the fixing roller 401 using the halogen lamp 407a is shown by a curve 407a, and the surface temperature distribution of the fixing roller 1 using the halogen lamp 407b is shown by a curve 407b.
The surface temperature distribution of the fixing roller 1 using the halogen lamp 407f is shown by a curve 407f.

As is apparent from FIG. 29, the temperature difference in the sheet passing area on the surface of the fixing roller 401 using the halogen lamp 407a is about 5 ° C. It has been confirmed that almost the same evaluation results can be obtained. It can also be seen that the surface temperature of the fixing roller 401 has reached a temperature sufficient for fixing.

On the other hand, the difference between the surface temperature at the center and the surface temperature at the end of the fixing roller 401 using the halogen lamp 407b is about 10 ° C. Therefore, the transfer material 41
A difference occurs between the gloss at the edge of 0 and the gloss at the center, and the difference is visually confirmed.

Although the surface temperature distribution of the fixing roller 401 using the halogen lamp 407f is substantially uniform, the surface temperature does not reach a predetermined fixing temperature, and
(1) The time required to raise the surface temperature to a predetermined fixing temperature is prolonged.

Next, a halogen lamp 407 is attached to the fixing device.
Another halogen lamp that can be used in place of a will be described. FIG. 27 is a configuration diagram showing another halogen lamp used in the fixing device of FIG.

As shown in FIG. 27, the other halogen lamps 407d are arranged along the axis of the fixing roller 401 at intervals from each other, and a plurality of tungsten filament portions 451, 452, 453, 454, 455,
456. The filament part 451 is the fixing roller 4
It is located at the center of 01 and its number is 401. On one side of the filament part 451, each filament part 45
2, 453, 454, 455, and 456 are arranged toward one end of the fixing roller 1. Filament part 4
On the other side of the filament part 451, similarly to the one side of the filament part 451, each filament part 452, 453, 454,
455 and 456 are arranged toward the other end of the fixing roller 401. Each filament part 451, 452,
453, 454, 455, and 456 have the same length, and the length is 22 mm.

The filament part 451 and the filament part 4
52, the distance between the filament 452 and the filament 453 is LB, the distance between the filament 453 and the filament 454 is LC, the distance between the filament 454 and the filament 455 is LD, and the distance between the filament 455 and the filament 455 is LB. LE is set to the distance from the filament part 456.
Then, the following relational expression LA>LB>LC>LD> LE is satisfied.

In this embodiment, the distance LA is set to 14 m.
m, interval LB is 10 mm, interval LC is 7 mm, interval LD
Is set to 4 mm, and the distance LE is set to 3 mm. However, it is preferable to set the ratio of the distance between the adjacent filament portions to a value in the range of 0.5 to 0.9.

As described above, the distance between the filament portions adjacent to each other of the halogen lamp 407d gradually decreases in the order of arrangement from the center of the fixing roller 401 to the end of each filament portion.
Since the amount of heat from 07d is uniformly supplied to the fixing roller 1 in the axial direction, the rising time until the surface temperature of the fixing roller 401 reaches the fixing temperature is shortened, and the next transfer material is introduced into the nip portion. By this time, the surface temperature of the fixing roller 401 can be raised to a predetermined fixing temperature, and the surface temperature distribution of the fixing roller 401 is made uniform again. As a result, the unfixed toe image on the next transfer material can be reliably fixed to the transfer material without causing a fixing failure.

Next, a halogen lamp 407 is attached to the fixing device.
Another halogen lamp that can be used in place of a will be described. FIG. 28 is a configuration diagram showing still another halogen lamp used in the fixing device of FIG.

As shown in FIG. 28, another halogen lamp 407e is provided at a distance from the fixing roller 40.
And a plurality of filament portions 429, 430, 431, 432, 4 made of tungsten arranged along one axis.
33, 434, 435 and 436. The filament part 429 is located at the center of the fixing roller 401, and the number thereof is one. On one side of the filament section 429, each filament section 430, 431, 432, 433, 43
4, 435, 436 are provided at fixed intervals.
01 are arranged toward one end. On the other side of the filament section 429, similarly to one side of the filament section 429, each of the filament sections 430, 431, 4
32, 433, 434, 435 and 436 are arranged at regular intervals toward the other end of the fixing roller 1.

Each filament section 429, 430, 431
Have the same length dimension, which is 10 mm. On the other hand, the length of the filament portion 432 is 1
2 mm, the length of the filament part 433 is 15 mm,
The length of the filament 434 is 19 mm, the length of the filament 435 is 27 mm,
The length dimension of 36 is 36 mm.

As described above, each filament portion 432, 4
Since the lengths of 33, 434, 435, and 436 gradually increase in the order of arrangement from the center to the ends of the fixing roller 401, the amount of heat from the halogen lamp 407e is uniformly supplied to the fixing roller 401 in the axial direction. Because
The rise time until the surface temperature of the fixing roller 401 reaches the fixing temperature is shortened, and the surface temperature of the fixing roller 401 can be raised to a predetermined fixing temperature before the next transfer material is introduced into the nip portion, Further, the fixing roller 4
01 is again made uniform. As a result, the unfixed toe image on the next transfer material can be reliably fixed to the transfer material without causing a fixing failure.

Next, a test for confirming the above-described effects was performed, and the results are shown in FIG. In this test, when the surface temperature of the fixing roller 401 is 20 ° C., the heating operation by the halogen lamp 407 e is started, and three minutes after the start of the heating operation, the surface temperature of the fixing roller 401 is measured, and the measured temperature is recorded.

As is clear from FIG. 29, the surface temperature at the center of the fixing roller 401 using the halogen lamp 407e is slightly higher than the surface temperature at the center of the fixing roller 401 using the halogen lamp 407a. The curve 407d showing the surface temperature distribution of the fixing roller 401 using the halogen lamp 407e in other parts is almost the same as the curve showing the surface temperature distribution of the fixing roller 401 using the halogen lamp 407a. Therefore, the temperature difference in the sheet passing area on the surface of the fixing roller 401 using the halogen lamp 407e is about 5 ° C., and almost the same evaluation result is obtained in the fixing area and glossiness in the entire sheet passing area. That has been confirmed. Further, the fixing roller 4
It can be seen that the surface temperature of No. 01 has reached a temperature sufficient for fixing.

In the present embodiment, the filament portions 432, 433, 434, and
Although the lengths of 435 and 436 are increased in the arrangement order of the filament portions, the filament portions 432 and 43
The above-described effect can be obtained by reducing the intervals of 3,434,435,436 in the order of arrangement of the filament portions.

Embodiment 8 Next, Embodiment 8 of the present invention will be described with reference to FIG. This embodiment is different from the conventional example in that two types of fixing devices having different configurations are prepared so as to be exchangeable, and a user or the like can select the fixing device at any time. In this embodiment, both the electrophotographic apparatus as shown in FIG. 38 capable of performing double-sided copying and the electrophotographic apparatus as shown in FIG. 35 capable of performing only one-sided copying will be described.

In FIG. 32, MA indicates a pressure roller 530.
Is a fixing device for single-sided fixing using a fluororesin 535 as a material of the surface layer, and MB is a fixing device for double-sided fixing using a RTV silicone rubber 533 'as a material of the surface layer of the pressure roller 530'. A fixing device detection unit 550 is formed integrally with the fixing device. The claw 551 indicates a single-side fixing unit, and a unit having both the claws 551 and 552 indicates a double-side fixing unit.

The detection of the nail may be performed by a conventionally known electric method or the like, and may be any other method such as light detection, current detection, and resistance detection.

When the color electrophotographic apparatus is for forming only a single-sided image as an image forming operation as in the conventional example of FIG. 35, a fixing apparatus MA for single-side fixing is usually incorporated in the electrophotographic apparatus. In this case, since the surface layer of the pressure roller 530 is made of fluororesin 535, the pressure roller 5
30 has a long life, and a long life can be achieved as an electrophotographic apparatus.

However, when the user or service person mistakenly incorporates the fixing device MB for double-sided fixing, the operation of the electrophotographic apparatus is not changed at all and normal single-sided image formation is performed. RT instead of fluoroplastic
There is a problem that the life of the pressure roller 530 'having the surface layer of V silicone rubber is shortened. Therefore, in the present embodiment, it is detected that the fixing device mounted by the claws 551 and 552 is for double-sided fixing, and the user or the service detects that the fixing device is erroneously mounted via an operation panel (not shown) or the like. It is set to notify a man or the like.

On the other hand, when the color electrophotographic apparatus is for double-sided image formation as in the conventional example of FIG. 38, a fixing device MB for double-sided fixing is usually incorporated. At this time, the nail 55
1 and 552 detect that the fixing device for double-sided fixing is incorporated, and the double-sided image formation as described in the conventional example is performed without any trouble. That is, since the surface layer of the pressure roller 530 'is formed of the RTV silicone rubber 533', offset can be effectively prevented and a good image can be provided.

However, since two types of fixing devices can be exchanged in the apparatus of the present embodiment, even when an electrophotographic apparatus for double-sided copying is mainly used for single-sided copying, for example, a single-sided fixing device is determined by a user's judgment. Fixing device MA can be mounted. As described above, when the fixing device MA is incorporated, it is detected by the claw 551 that the fixing device is a single-side fixing device, and the double-sided image formation is not performed. This is done so as not to accept the double-sided copy switch on the operation panel (not shown),
1 can be prohibited. For this reason, when the single-sided fixing device is mounted, double-sided copying is not performed erroneously, and occurrence of offset can be prevented beforehand. Since the fluororesin 35 is used for the surface layer of the pressure roller 530, the durability can be increased.

Also, contrary to the wishes, fixing device MA for one-side fixing
Is attached, the double-sided copy operation is prohibited as described above, so that a user or a service person can immediately know the erroneous attachment.

By detecting the fixing device MA for single-sided fixing and the fixing device MB for double-sided fixing as described above, the service life of the fixing device can be extended in single-sided fixing. It was possible to prevent the toner image from being offset to the side and to cause a problem, and it was possible to perform satisfactory double-sided fixing. Further, erroneous mounting of the fixing device in each case could be reliably prevented.

<Embodiment 9> Next, Embodiment 9 of the present invention will be described with reference to FIG. The same parts as in the eighth embodiment are denoted by the same reference numerals, and the description is omitted.

This embodiment is different from the eighth embodiment in the material of the surface layer of the fixing roller. In FIG. 33, the material of the surface layer of the fixing roller 529 of the fixing device MC for black and white copying is fluororesin 53.
3 ″, and the fixing roller 5 of the fixing device D for color copying.
RTV silicone rubber 533 is used as the material of the surface layer of No. 29. Also in the present embodiment, the claw 551 detects the fixing device MC, and the claws 551 and 552 detect the fixing device MD.

In the case of a color electrophotographic apparatus as in the conventional examples shown in FIGS. 35 and 38, the operation is enabled only when the nails 551 and 552 detect that the fixing apparatus MD for color copying has been incorporated. That is, in the case of a sharp-melt color toner in which offset is likely to occur, the fluororesin of the fixing device MC for black-and-white copying as a material of the surface layer of the fixing roller is offset because of no affinity with oil. Therefore, when the black-and-white copy fixing device MC is incorporated, the copy switch of the operation plate (not shown) may not be accepted.

On the other hand, when the black-and-white copying fixing device MC is incorporated in a copying device using a low-melting-point, non-sharp-melt toner, such as a conventionally known black-and-white copying device, the copying operation is enabled by detection.

<Embodiment 10> Next, Embodiment 10 of the present invention will be described.
Will be described with reference to FIG. Note that the same parts as those in the eighth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is an apparatus capable of increasing the gloss of an image after fixing. In FIG. 34, the fixing device ME
A fixing device for one-sided copying using a fluororesin on the surface layer of a pressure roller similar to the fixing device MA of FIG.

The fixing device MH is a fixing device for double-sided copying using RTV silicone rubber on the surface of a pressure roller similar to the fixing device MB in FIG. 32 detected by the claws 551 and 552.

Further, the fixing device MF is detected only by the claw 552, and the fixing roller MF is a fixing device of the RTV silicone rubber in which the material of the surface layer of the fixing roller and the material of the surface layer of the pressing roller are the same as the fixing device H. This is a fixing device for increasing gloss in double-sided copying, which is set to have a temperature of 200 ° C. By increasing the heating amount in this manner, the toner can be melted well and gloss can be increased.

[0200] The fixing device MG is detected without a claw, and a fixing device for increasing gloss in single-sided copying in which the material of the surface layer of the fixing roller and the material of the surface layer of the pressure roller are made of fluororesin similarly to the fixing device ME. Device. The fixing temperature is set to be 200 ° C. which is the same as the fixing device MF. Due to this, the gloss of the image is increased by the fixing device M.
Similar to F, but the fixing device MG is a fixing device for one-sided fixing.

In the present embodiment, each of the above fixing devices is prepared so as to be exchangeable by a user or a service person, and the image forming operation includes a normal gloss on one side, a normal gloss on both sides, and a normal gloss on both sides. Gloss increase and gloss increase on both sides can be selected, and erroneous mounting in each case can be prevented. Further, the fixing device M
E and MG make it possible to extend the life, and the fixing devices MH and MF make it possible to prevent offset in double-sided copying.

In the embodiment described above,
Although the fixing device is detected based on the presence or absence of the claws 551 and 552, the number of claws is not limited to this. Further, other methods such as providing concave portions having different positions at predetermined positions of the respective fixing devices may be used. Also,
In addition to the method in which the fixing device is automatically identified by the fixing device detecting unit attached to the fixing device in this manner, the operation panel (not shown) and the like can be provided by attaching a seal or the like to the fixing device so that the type can be identified. The identification signal may be given by the following.

When each type of fixing device is selected,
A display may be displayed on an operation panel (not shown), and a glossy copy or the like may be displayed in the case of increasing the gloss as in the fixing devices MF and MG.

Further, in the above-described embodiment, several types of detection examples such as single-sided, double-sided, color, black-and-white, and gloss increase have been described. Needless to say, fine detection may be performed.

[0205]

As described above, according to the first aspect of the present invention, there is provided a rotating body pair including a fixing rotating body and a pressing rotating body, and a heating element is provided inside at least one of the rotating bodies. In the fixing device that heats the rotating body by using, between the recording material passing portion of the rotating body core metal and the rotating body holding portion at the end,
By inserting a heat insulating material having a lower thermal conductivity than the core metal, a stable amount of heat is supplied in the axial direction of the rotating body, and a stable fixing property can be secured over the entire recording material. Warm-up time can be reduced.

[0206]

[0207] in the following, according to the second invention, in the fixing device of the image forming apparatus of one side reference, at the time of a small size sheet passing is
By forming an airflow around the fixing roller from the non-reference side to the reference side in the longitudinal direction of the roller, it is possible to reduce the temperature rise of the non-paper passing part and to recycle heat in the non-paper passing part to the paper part. Effective use of energy has become possible.

According to the third aspect of the present invention, the length of each filament portion of the halogen lamp is increased in the order of arrangement from the center to the end of the rotating body, so that the halogen lamp supplies the rotating body to the rotating body. Since the amount of heat to be applied becomes uniform in the axial direction of the rotating body, the rising time until the surface temperature of the rotating body reaches the fixing temperature is shortened, and the rotating time until the next transfer material is introduced into the nip portion is reduced. The surface temperature of the body can be uniformly and quickly raised to a predetermined fixing temperature.

Further, according to the fourth aspect of the present invention, the halogen lamp is supplied from the halogen lamp to the rotating body because the interval between the filament portions of the halogen lamp is smaller in the arrangement order from the center to the end of the rotating body. Since the amount of heat becomes uniform in the axial direction of the rotating body, the rising time until the surface temperature of the rotating body reaches the fixing temperature is shortened, and the rotating body of the rotating body is introduced until the next transfer material is introduced into the nip portion. The surface temperature can be raised uniformly and quickly to a predetermined fixing temperature.

According to the fifth aspect of the present invention, a plurality of fixing devices having different applications are interchangeably disposed and identification means for each fixing device is provided, so that the image forming apparatus can be diversified by one image forming device. Various image formations that meet needs can be performed at any time, and malfunctions can be prevented. further,
Since the type of the mounted fixing device can be identified by the identification means, erroneous mounting at the time of maintenance or replacement can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of an apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a flow of heat in a core metal of a fixing rotating body of the apparatus in FIG. 1;

FIG. 3 is a diagram showing a light distribution of a heating element used in an experimental example of Example 1.

FIG. 4 is a diagram showing a thickness of an end portion of a core of a fixing rotating body and an axial thickness of a heat insulating material in the apparatus of FIG. 1;

FIG. 5 is a diagram showing an axial distribution of a surface temperature of a fixing rotating body in an experimental example of Example 1.

FIG. 6 is a diagram illustrating a temperature difference between a recording material passage portion and an end portion of a fixing rotating body in an experimental example of Example 1.

FIG. 7 shows an experimental example of Example 1 in which the temperature difference in FIG.
It is a figure which shows the relationship of thickness and thermal conductivity of a thermal barrier at 5 degreeC.

FIG. 8 is a cross-sectional view perpendicular to the axial direction of a fixing rotating body of the conventional apparatus corresponding to the first embodiment.

FIG. 9 is a cross-sectional view parallel to the axial direction of a fixing rotating body of a conventional apparatus corresponding to the first embodiment.

FIG. 10 is a sectional view showing a schematic configuration of an apparatus according to a second embodiment of the present invention.

11 is a view for explaining the position of a reflecting mirror when a recording material having a maximum size is conveyed to the apparatus in FIG. 10;

12 is a diagram for explaining the position of a reflecting mirror when a small-sized recording material is conveyed to the apparatus in FIG. 10;

FIG. 13 is a diagram illustrating a change in the surface temperature of the fixing roller when the reflecting mirror is at the position shown in FIG. 12;

FIG. 14 is a sectional view showing a schematic configuration of an apparatus according to a third embodiment of the present invention.

FIG. 15 is a control diagram according to a fourth embodiment of the present invention.

FIG. 16 is a diagram illustrating a change in the surface temperature of the fixing roller when the control of the fourth embodiment is performed.

FIG. 17 is a cross-sectional view illustrating a schematic configuration of a conventional device corresponding to Embodiments 3 and 4.

18 is a diagram illustrating a change in the surface temperature of a fixing roller in the apparatus in FIG. 17;

FIG. 19 is a perspective view illustrating a schematic configuration of an apparatus according to a fifth embodiment of the present invention.

20 is a cross-sectional view for explaining a space SA formed between a guide plate provided above the fixing roller of the apparatus of FIG. 19 and the fixing roller.

FIG. 21 is a view for explaining the flow of air and the flow of heat above the surface of the fixing roller when the blowing means is driven in the apparatus of FIG. 19;

FIG. 22 is a perspective view illustrating a schematic configuration of an apparatus according to a sixth embodiment of the present invention.

FIG. 23 is a cross-sectional view showing a schematic configuration of a conventional apparatus for Examples 5 and 6.

FIG. 24 is a view showing a light distribution of a heating means of the apparatus of FIG. 23;

FIG. 25 is a sectional view showing a schematic configuration of an apparatus according to a seventh embodiment of the present invention.

26 is a configuration diagram showing a halogen lamp used in the apparatus in FIG. 26.

FIG. 27 is a configuration diagram showing another halogen lamp used in the apparatus in FIG. 25.

FIG. 28 is a configuration diagram showing still another halogen lamp used in the apparatus of FIG. 25;

FIG. 29 is a diagram showing the distribution of the surface temperature of each of the fixing rollers incorporating the halogen lamp of FIG. 26, the halogen lamp of FIG. 28, and the conventional halogen lamp.

FIG. 30 is a configuration diagram illustrating an example of a halogen lamp used in a conventional fixing device corresponding to a seventh embodiment.

FIG. 31 is a configuration diagram showing another example of the halogen lamp used in the apparatus in FIG. 30.

FIG. 32 is a cross-sectional view illustrating a schematic configuration of two types of fixing devices in an apparatus according to an eighth embodiment of the present invention.

FIG. 33 is a cross-sectional view illustrating a schematic configuration of two types of fixing devices in a ninth embodiment of the present invention.

FIG. 34 is a cross-sectional view illustrating a schematic configuration of four types of fixing devices in a tenth embodiment of the present invention.

FIG. 35 is a cross-sectional view showing a schematic configuration of a conventional image forming apparatus capable of performing one-sided color copying corresponding to the eighth to tenth embodiments.

36 is a cross-sectional view showing a plunger lowering amount with respect to a temperature of toner used in the apparatus of FIG. 35.

FIG. 37 is a sectional view showing a schematic configuration of a fixing device used in the apparatus of FIG. 35;

FIG. 38 is a sectional view showing a schematic configuration of a conventional image forming apparatus capable of performing double-sided color copying corresponding to the eighth to tenth embodiments.

FIG. 39 is a cross-sectional view illustrating a schematic configuration of a fixing device used in the apparatus of FIG. 38;

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Rotating body for fixing 100a Core metal 100b RTV silicone rubber layer (elastic body layer) 101 Heat blocking material 102 Recording material passing section 103 End holding section (rotating body end section) 211 Fixing roller (rotating body for fixing) 212 Pressure Roller (rotating body for pressing) 216 Heater (heating means) 220, 221a Reflecting mirror 301 Fixing roller (rotating body for fixing) 302 Pressure roller (rotating body for pressing) 303 Halogen heater (heating means) 310 Fan (blowing means) 311 Duct (air blowing means) 401 Fixing roller 402 Heating roller 407a, 407d, 407e Halogen lamp 410 Transfer material 411 Toner image 413, 414, 415, 416, 417, 418, 4
19,420 Filament part 429,430,431,432,433,434,4
35,436 Filament part 451,452,453,454,455,456 Filament part 550 Fixing device detecting unit (Fixing device identification means) 551,552 Claw (Fixing device identification means) MA Single-side fixing fixing device MB Double-side fixing Fixing device for MC MC fixing device for black and white MD Fixing device for color ME Normal fixing device for gloss in single-side fixing MF Fixing device for increasing gloss in double-side fixing MG Fixing device for increasing gloss in single-side fixing MH Normal fixing for gloss in double-side fixing apparatus

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasushi Yasura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akio Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Tatsuo Takeuchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Jiro Ishizuka 3-2-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. 72) Inventor Haruo Naruse 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Moto Kato 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (72) Inventor Ken Koshijo, Canon Inc., 3-30-2 Shimomaruko, Ota-ku, Tokyo (56) References JP-A-2-163784 (JP, A) JP-A-1-314274 (JP, A) JP-A-63-249874 (JP, A) JP-A-63-85764 (JP, A) JP-A-4-174484 (JP, A) Full-scale application Sho 61-116371 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) G03G 15/20 G03G 15/01

Claims (8)

(57) [Claims] 1. A rotating body pair comprising a fixing rotating body and a pressing rotating body having an elastic layer on a cored bar, and a heating means disposed inside at least one of the rotating bodies of the rotating body pair. In the fixing device, the core of the rotating body provided with the heating means is provided between the end of the rotating body to which the supporting member or the driving member of the rotating body is attached and the recording material passing portion of the rotating body. Is inserted with a thermal barrier material having a lower thermal conductivity than the core metal, and the thermal barrier material has a thermal conductivity
Is λ, the thickness of the thermal barrier in the axial direction of the rotating body is t,
Is the thermal conductivity of λ ₀ , and the thickness of the end of the core metal is r ₀ ,
It is set to satisfy the equation of _{100 × λ / t ≦ λ 0} / r 0
A fixing device characterized in that is. 2. The heat insulating material is made of stainless steel,
2. The fixing device according to claim 1, wherein one of various heat-resistant plastic materials and various ceramic materials is used. 3. A fixing rotating body having a heating means,
The recording material is conveyed based on the axial end of the fixing rotator
In the fixing device for performing fixing, the fixing
Air is blown from the non-paper passing reference side in the axial direction
A fixing device comprising a blowing unit for sending air to a secondary side . 4. A pair of rotating bodies which rotate while being pressed against each other and form a nip for cooperating and conveying a transfer material, and at least one of the rotating bodies is provided inside the rotating body. A fixing device provided with a halogen lamp for heating the surface of the rotating body, wherein the halogen lamp includes a first filament group arranged at a central portion of the rotating body, and the first filament group. A second filament group disposed on one side of the group, and a third filament group disposed on the other side of the first filament group, wherein the first filament groups are mutually separated. The second filament group is spaced apart from each other along the axis of the rotating body, and the second filament group is spaced apart from one side of the first filament group. A plurality of filament portions arranged along an axis of the rotating body toward one end of the body, wherein the third filament group is spaced apart from each other and the other side of the first filament group. Consisting of a plurality of filament portions arranged along the axis of the rotating body toward the other end of the rotating body, wherein the rotating body in the first filament group and the second filament group From the central portion of the rotating body in the first filament group and the third filament group to the other end portion of each of the filament portions arranged from the central portion toward one end thereof. Each of the arranged filament portions is arranged symmetrically with respect to the center portion of the rotating body, and the length dimension of each filament portion constituting the second filament group and the Third length dimension of each filament portion constituting the filament group is fixing apparatus characterized by increased gradually in the arrangement order towards its end from the central portion of the rotating body. 5. The length of each filament portion arranged from the central portion of the rotating body in the first filament group and the second filament group toward one end thereof gradually increases in the order of arrangement. In the first filament group and the third filament group, the length dimension of each filament portion arranged from the central portion of the rotating body to the other end portion gradually increases in the arrangement order. The fixing device according to claim 4 . 6. A pair of rotating bodies that rotate while being pressed against each other and form a nip for cooperating and conveying a transfer material, and at least one of the rotating bodies inside the rotating body. A fixing device provided with a halogen lamp for heating the surface of the rotating body, wherein the halogen lamp includes a first filament group arranged at a central portion of the rotating body, and the first filament group. A second filament group disposed on one side of the group, and a third filament group disposed on the other side of the first filament group, wherein the first filament groups are mutually separated. The second filament group is spaced apart from each other along the axis of the rotating body, and the second filament group is spaced apart from one side of the first filament group. A plurality of filament portions arranged along an axis of the rotating body toward one end of the body, wherein the third filament group is spaced apart from each other and the other side of the first filament group. Consisting of a plurality of filament portions arranged along the axis of the rotating body toward the other end of the rotating body, wherein the rotating body in the first filament group and the second filament group From the central portion of the rotating body in the first filament group and the third filament group to the other end portion of each of the filament portions arranged from the central portion toward one end thereof. Each of the arranged filament portions is arranged symmetrically with respect to the central portion of the rotating body, and the distance between the filament portions constituting the second filament group and the third filament portion are arranged. Intervals of each filament portion constituting the filament group is fixing apparatus characterized by reduced gradually in the arrangement order towards its end from the central portion of the rotating body. 7. The spacing between the filaments arranged from the center of the rotating body in the first filament group and the second filament group to one end thereof gradually decreases in the order of arrangement. In the first filament group and the third filament group, the interval between the filament portions arranged from the central portion of the rotating body to the other end portion gradually decreases in the arrangement order. the fixing device according to one of claims 4 to 6. 8. An image forming apparatus having a fixing device for fixing an unfixed image on a transfer material obtained by the operation of the image forming device to form a permanent image, the image forming device comprising a plurality of fixing devices having different purposes. applications but is freely exchanged at any time, provided with means for identifying each fixing device, identified fixing device
Is set to perform the image forming operation according to
An image forming apparatus .